• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.413-416
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• 1997

In this paper, we propose a new single-stage isolated switching power supply. The proposed converter reduces the diode conduction loss and offer both the high input Power factor and the direction conversion from the ac line to a dc output voltage. This paper present the Operational principle, analysis and control and experimental results of a 100W prototype.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.145-149
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• 2000

A single-stage power factor correction AC/DC converter with a simple link voltage suppressing circuit (LVSC) for the universal line application is proposed. Using this simple circuit a low link voltage can be realized without deadbands at line zero-crossings. The proposed converter is analyzed and a prototype converter with 5C, 12V output is implemented to verify the performance. The experimental results show that the link voltage stress and efficiency are about 447V and 81%, respectively.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1116-1120
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• 1987

In this paper, the Adjacency Matrix is applied to analyze the MIN, which is one of the kind and further implemented in designing the new kind of SSIN, which provides the special form of MIN that has identical link patterns between switching stages. At first, new theorems are established and next the classes of the SSIN are generated from computer simulation.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.626-630
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• 1999

A new integrated single-stage zero current switched(ZCS) quasi-resonant converter (QRC) for the power factor correction(PFC) converter is introduced in this paper. The power factor correction can be achieved by the discontinuous conduction mode(DCM) operation of an input current. The proposed converter has the characteristics of the good power factor, low line current harmonics, and tight output regulation. Furthermore, the ringing effect due to the output capacitance of the main switch can be eliminated by use of active clamp circuit.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.418-422
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• 1998

A new single stage AC/DC converter based on the forward converter is proposed. The proposed converter offers both the high power factor and the direct conversion from ac line to dc output voltage. Also, the proposed converter reduces the diode conduction loss, so improves the overall efficiency of the converter, compared with other alternatives. The principles of operation and the simulation results of the proposed converter are presented. A 100 W prototype was built and tested to show the potential of applications of the proposed converter.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.438-443
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• 1998

A simple single-stage AC/DC forward converter with transformer magnetic energy feedback technique for power factor correction is proposed. The operational principle of the proposed converter is presented. The proposed converter gives the good power factor correction, low line current harmonic distortions, and tight output voltage regulation. The prototype shows high power factor with low line current harmonics.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.1
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• pp.43-55
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• 2009

Advanced countries in aerospace have been struggle to realize the hypersonic air-breathing system since originating the concept of the hypersonic air-breathing propulsion system during the first half of the twentieth century. At last, NASA's X-43A Hyper-X did successful Mach 10 flight in November 2004. Each countries are running the program to applicate this hypersonic air-breathing propulsion system to SSTO(Single Stage to Orbit) or TSTO(Two Stage to Orbit) vehicle or hypersonic missile system at present. In this paper, we wrote the history and current issues of the hypersonic air-breathing propulsion system and hypersonic flight with the hypersonic air-breathing propulsion system.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.5
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• pp.195-204
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• 2018

In this paper, we propose both a new loss function and an online hard example mining scheme for improving the performance of single-stage object detectors which use deep convolutional neural networks. The proposed loss function and the online hard example mining scheme can not only overcome the problem of imbalance between the number of annotated objects and the number of background examples, but also improve the localization accuracy of each object. Therefore, the loss function and the mining scheme can provide intrinsically fast single-stage detectors with detection performance higher than or similar to that of two-stage detectors. In experiments conducted with the PASCAL VOC 2007 benchmark dataset, we show that the proposed loss function and the online hard example mining scheme can improve the performance of single-stage object detectors.

• Archives of Plastic Surgery
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• v.47 no.5
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• pp.460-466
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• 2020

Background Sternoclavicular joint (SCJ) osteomyelitis is a rare pathology requiring urgent intervention. Several operative approaches have been described with conflicting reports. Here, we present a multi-institutional study utilizing multiple surgical pathways for SCJ reconstruction. Methods A multi-institutional retrospective cohort study was conducted to identify patients who underwent surgical repair for sternoclavicular osteomyelitis between 2008 and 2019. Patients were stratified according to reconstruction approach: single-stage reconstruction with advancement flap and delayed-reconstruction with flap following initial debridement. Demographics, operative approach, type of reconstruction, and postoperative outcomes were analyzed. Results Thirty-two patients were identified. Mean patient age was 56.2±13.8 years and 68.8% were male. The average body mass index (BMI) was 30.0±8.8 kg/㎡. The most common infection etiologies were intravenous drug use and bacteremia (both 25%). Fourteen patients (43.8%) underwent one-stage reconstruction and 18 (56.2%) underwent delayed two-staged reconstruction. Both single and delayed-stage groups had comparable rates of reinfection (7.1% vs. 11.1%, respectively), surgical site complications (21.4% vs. 27.8%), readmissions (7.1% vs. 16.6%), and reoperations (7.1% vs. 5.6%; all P>0.05). The single-stage reconstruction group had a significantly lower BMI (26.2±5.7 kg/㎡ vs. 32.9±9.1 kg/㎡; P<0.05) and trended towards shorter hospital length of stay (11.3 days vs. 17.9 days; P=0.01). Conclusions Both single and delayed-stage approaches are appropriate methods with comparable outcomes for reconstruction for SCJ osteomyelitis. When clinically indicated, a single-stage reconstruction approach may be preferable in order to avoid a second operation as associated with the delayed phase, and possibly shortening total hospital length of stay.

• Journal of Korean Neurosurgical Society
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• v.59 no.2
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• pp.122-128
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• 2016

Objective : To illustrate the technique of single-stage posterior subtotal corpectomy and circumferential reconstruction for the treatment of unstable thoracolumbar burst fractures and to evaluate the radiographical and clinical outcomes of patients treated using this technique. Methods : 16 consecutive patients with unstable thoracolumbar burst fractures were treated with single-stage posterior subtotal corpectomy and circumferential reconstruction. The mean patient age was 54.8 years. The mean follower up period was 25 months. Five patients suffered from T12 fractures, 10 from L1, 1 from L2. The segmental kyphosis, neurologic status, visual analogue scale for back pain was evaluated before surgery and at follow up. Results : The segmental kyphotic angle improved from 18.5 degrees before surgery to -9.2 degrees at the last follow up. The mean correction angle was 28.9 degrees. The mean surgical time was 255 minutes, and a mean intraoperative blood loss was 1073 mL. Intraoperative complications included two dural tears, and a superficial wound infection. There were no other severe complications. The mean visual analog scale of back pain decreased from a mean value of 6.6 to 2 at the last follow up. Conclusion : The single-stage posterior subtotal corpectomy and circumferential reconstruction achieved satisfactory kyphosis correction with direct visualization of the circumferentially decompressed spinal cord, as well as good fusion with less blood loss and complications. It is a safe and reliable surgical treatment option for unstable thoracolumbar burst fractures.